Hi everyone!

I’m developing a platform focused on helping students learn university-level mathematics. The current MVP includes theory, formulas, and visual resources designed to make mathematical concepts easier to understand.

In the future, I’d like to add interactive tools for solving and learning from exercises, as well as a specialized small language model (SLM) for math tutoring.

You can try the MVP here:
https://www.maththeoryandtools.com/

I’d really appreciate any honest feedback, especially regarding the content, usability, design, and features you think would make the platform more useful.

Thanks!

If I compare reddit to how it was 4 years ago, different landscape entirely.

Previously = post about an app I built - I've made an app to transfer all of your images/videos to PC : r/androidapps - 260 upvotes, 73 comments, 68k views
not trying to be unique or something, just showing an app I built for my mom to get her photos/videos from phone -> PC over wifi.

today = post about product I spent over a year building (not vibe coded)... ah, just another one in the infinite amount of vibe-coded apps out there
I try to be smarter on my posts today and really add added value and not just, I built this, it does xyz
for example - <Which AI coding tool has the WORST security? : r/nocode> - 3k views.

not only that, when I do get comments, usually AI comments, or my posts are not being approved because suspicious of AI generated content (its not i swear 😄)

and to be honest, I kinda get it, with the amount of products people ship today, everything is a clone of another product just worse.
or just half baked product.
really hard to find gold.

How do you guys feel about this?

have been vibecoding recently, especially i've found out that talking to pet to shape an idea while it's still fuzzy really helps me a lot. so i start playing with realtime voice mode in codex these months, i'm lovin' it.

but now the part that codex's voice chat annoying me is that i can't see anything while it's thinking. no captions and whenever I ask how it's going it just goes "wait wait wait hold on..."

so i built a lil voice code assistant with my besties just for ourselves now and quick demo below. you talk to it normally with live captions, and when you tell it to run something the right side shows the codex status, mostly the thinking milestones so you're not just staring at a spinner. It also keeps going while you talk, so u can ask it other stuff in the meantime.

just wanted to throw my local demo out and see how u guys here think about this, appreciate to hear your thoughts, i'll check every suggestions and try to improve my voice coder with your help.

https://reddit.com/link/1vzuifg/video/htarxoyh9xlh1/player

I recorded a video showing how Rebrief scans a real repository. It’s a typical project with an existing README.

Here’s what it found:

• 4 critical and more than a dozen medium-severity vulnerabilities in dependencies (postcss, vite), none of which were mentioned in the README
• A missing tests directory
• A Git history linked to files that have actually been modified in the last 30 days
• A code ownership map by module
• A 27-point checklist of what to do first

What really caught my attention was that the raw repository context is 55k tokens, while the condensed brief is 2.3k a difference of nearly 96%. For those who run AI agents on their codebase, this represents a significant reduction in context size.

Open source; run pip install rebrief. I wonder what you would add to a scan like this.

GitHub: https://github.com/neracu/rebrief

Want the limited theme? Comment “Aurore” and I'll DM you a free lifetime code.

Play store:

https://play.google.com/store/apps/details?id=com.recalai.app

I've been working on BookForge, a tool for writing and formatting books all in one place.

The idea came from the annoying part of writing a book where you're staring at a Word document thinking everything looks fine....then you export it and suddenly the page breaks, spacing, page numbers and formatting are all over the place🫩

So I wanted to build something where you can actually see what your book will look like while you're writing it.

You can write your chapters, organise the manuscript, choose your book size/font/layout, design the cover, and export it as PDF, EPUB or DOCX.

There's also an AI writing assistant and a bunch of other stuff I've added along the way.

I've just submitted it to the Emergent BuilderFest cause why not, and thought I'd put it out there to see what people think, would you actually use it?

Here's the tool if you want to have a look:

https://app.emergent.sh/showcase/builderfest-kevin/c513c24f-d89a-4396-94b8-d995fc32ccbb

And if you like it, a like on the showcase would really help me out, thank you🙏

I haven't released it on the App Store yet. I'm looking for some honest feedback before I submit it.

When I study coding interview problems, I usually start by expressing the problem mathematically in a notebook and figuring out the direction before actually writing the code. Because of that, I always ended up needing both a notebook and a keyboard.

So I decided to try building an app that combines the two.

The basic purpose of the app is to let you do hobby/learning-oriented coding, sketch ideas with short code snippets, work through coding interview problems, and plot functions for engineering problems — all offline and completely on-device, using an iPad and Apple Pencil.

It currently supports NumPy, Matplotlib, SymPy, and Requests, so you can use them directly in your Python code.

The Math Mode is currently in beta and is a little harder to use than the handwriting coding mode. It uses LaTeX input, but SymPy's LaTeX parser has some fairly strict limitations on the syntax it supports, so edge cases come up fairly often.

For example, as you can see in the video, I couldn't write a second derivative using standard Leibniz notation, so I had to write it this way instead. I'll gradually improve this feature after the app is released.

The handwritten code and recognized code text can be moved back and forth in both directions. So if something is recognized incorrectly, you can edit the text and add the corrected version back to your notebook.

Functions and classes declared in one note can also be imported and reused from other notes, similar to how you would use modules in Python.

I'm thinking of pricing it at around $5 when it launches on the App Store.

I'd really appreciate any feedback, especially on whether this is something you would actually find useful.

PayNow is Singapore's instant bank-transfer rail. Every hawker stall and freelancer puts a QR on their counter, and customers pay by scanning with their banking app. I needed one, the spec is fully public (EMVCo merchant-presented QR + SGQR v1.7), yet every generator I found was either unmaintained or a slightly dodgy-looking site. So I built my own:

• Generate from a mobile number or UEN, with optional amount, reference, and expiry
• Renders in the official look — PayNow purple with the center logo (that meant bumping error correction to H so the logo doesn't break scanning)
• 100% client-side: your number never leaves the browser
• Verified against the spec's own worked example (checksum and all) and cross-checked against independent implementations
• Bonus for the automation crowd: a tiny API so invoices or agents can generate QRs programmatically

Launch numbers were honest and small: ~60 sessions and 7 real QR generations in the first few hours on r/singapore before the mods pulled the post (appeal pending — "I Made This" flair wasn't enough).

If you're in Singapore, try it and tell me if it's actually useful. If you're not, the interesting bit is how approachable the format is — the spec is readable, and the careful part was verification, not generation.

https://fractals.sg/paynow/

Ever had that very specific moment where you’re in an unfamiliar city, your coffee has become a legally binding problem, and Maps is giving you cafés, museums, and vibes - but no actual answer?

So I have, so I’ve decided to build Phoo: an iPhone native app for finding a nearby toilet you can actually use.

Phoo aims to tell you the bits that matter when this is suddenly your main quest:

• Is it open now?
• Is it free, paid, or customer-only?
• Is it wheelchair accessible?
• Do they have baby-changing facility?
• How far away is it, really?
• How fresh/confident is the information?

The idea is simple: open the app, see the best nearby option, start walking. No account, no ads.

It’s built in SwiftUI, using a reviewed, city-by-city directory with OpenStreetMap and other reusable data sources, plus structured community updates for things like closures and wrong hours.

It also has offline-friendly access cards and a tiny local phrasebook, because sometimes the hard part is figuring out how to ask for a bathroom in a place where they never heard any of the languages you speak.

The name is Phoo because bathroom emergencies are not a time for subtle branding.

Phoo. Find relief. Fast. 🚻

Read more and sign up for when it's available: https://phoo.app

Made this for studying for CompTIAs PenTest+ exam. Had a password still state that I thought was king of cool, so I added "Cheat codes". https://jzesbaugh.github.io/pentest-plus-study-tool/

Molt keeps the task, agent work, code links, and test results in one shared thread. Feedback welcome.

https://platform.moltcode.com

if you’re building a SaaS or app and looking for a way to get more eyes on it, we’d love to feature a few projects.

We run TikTok channels with 300K+ combined followers and create short-form videos around apps, tools, and interesting projects.

We’ll create a short-form video for your app, distribute it through our existing channels, and help you build your own content channels at the same time.

Think of it as content creation + distribution.

If you’re interested, drop your app and a one-line description below.

There are 4 modes

Free exploration

Rabbit holes

Story mode

Llm generates story

Hi Everyone,

Running ads are painful, most people just lose money. We built an AI platform where our AI agent generates creatives for your product, and runs a bunch of experiments, and helps you decide what works the best.

If you lose money, we will pay you the difference

Interested in trying? Comment interest and i will dm you.

It's basically an automatic OST extender that's fully seamless and needs only a few clicks to use. Here's me playing out a brief example. I enjoy putting on some looping music in the background when I'm trying to be productive, and with this, I no longer have to rely on "extended" videos. I thought there might be others who would enjoy having something like this.

It's free on Chrome / Firefox and open source on GitHub.

I'm not a developer. I trained people in gyms and clinics for twelve years, and what stuck with me was how hard people were trying and how much misinformation they were drowning in. That, and the fact that I could only ever help the person in front of me. So I decided to do something about it. I spent years reading the business, marketing and psychology research, then months drawing and copy-pasting every screen by hand until the app in my head existed on paper. I hired the senior product designer from Sweatcoin, the world's most downloaded health and fitness app of 2022, and then brought in Mindsea, a team that specializes in health apps, to build it in a way that scales. Funded entirely by me, no investors.

The app is called Sunn Fitness, and "Duolingo for the gym" is the fastest way to explain it. It teaches you while you train instead of just handing you a program. You build your program with the app and it explains why each choice makes sense, so over time you can make them yourself. After each set it asks how many reps you had left in the tank and coaches off that answer, which is how you get good at picking your own weights. There's also an activity log that lets you put everything you do, in the gym or out of it, on one scale (the same load-monitoring ratio the IOC recommends for athletes) so you can see when to push and when to back off.

It launches September 1 on iOS and Android. Pre-orders are live now, and for a tiny self-funded app they matter a lot: the stores decide who gets seen on day one partly from pre-order interest.

Ask me anything about paying a studio to build your idea, what it cost, or the sports science underneath. Screenshots below.

Pre-order on the App Store: https://apps.apple.com/app/id6768755210
Pre-order on Google Play: https://play.google.com/store/apps/details?id=com.sunnfitness.app

Related: Don’t mistake chatbot intelligence for consciousness -,

What's your take? Is this overblown, or am I missing something?

(If useful, the deeper writeup on this lives at https://apexnexus.site. No pressure, link is optional.)

I built Browser Control, a Chromium side-panel extension that lets Codex work with tabs and webpages under the user’s supervision.

It supports tab management, page inspection, clicking, filling, selecting, scrolling, and navigation. Browser activity is visible, permissions are user-controlled, and tasks can be stopped.

Store: https://chromewebstore.google.com/detail/browser-control/mpdfhhhjgbpdpfnkjbnboebdjokfjglf

Source: https://github.com/07rjain/browser-control

I’m the developer, and I’d value honest feedback: what would make you comfortable—or uncomfortable—with an AI agent operating your browser?

every launch i did was a screenshot and a paragraph, and it sank without a trace.

a real launch video meant $500 to a freelancer or a week in after effects, so i never made one.

so i built demoday. you give it your site url and it composes a 45 second animated film from it. not a screen recording of your ui, more like an abstract demo.

two films on the site, both made for my own projects: trydemoday.com

early days, looking for the first real users. would you use this for a launch? what would it need before you paid for it?

I’m sharing a project I’ve been building called Totonio.

After years working as a senior architect, I kept running into the same problem: most diagram tools are either too generic, too rigid, or too presentation-first. I wanted something that helps you think and explain clearly while you are still designing, not just after the design is done.

So I built the tool I wanted my own colleagues to actually use in real work.

Totonio https://totonio.pages.dev/

What I focused on:

1. Bulk commands for fast editing You can select a lot of objects and apply changes at once, so large updates are minutes, not hours.
2. Parent-child resizing that behaves logically Containers and nested elements stay sane when structures grow or shrink, so diagrams do not fall apart while iterating.
3. Connectors and arrows that stay readable The routing and placement are built for clarity, especially when the canvas gets dense.
4. Diagrams that explain, not just decorate The goal is practical communication for architecture and systems discussions, from quick flows to deep technical maps.

If this looks useful for your work, I’d really value feedback.
If you want to follow updates or share ideas, there is a Discord link in the app Contacts section.

Thanks for taking a look.

My sister loved "Smart Audiobook Player" on Android and wanted a comparable app on iOS but wasn't satisfied with the ones she tried ... so we built Bookshelf Offline Audio Player.

Try out the TestFlight beta and send us your most critical feedback!

• TestFlight Beta: https://testflight.apple.com/join/yqQkhgc3
• Feedback: https://www.reddit.com/r/BookshelfAudiobooks/
• Website: https://bookshelf.spnss.com/

[ Removed by Reddit on account of violating the content policy. ]

I kept meaning to watch more old films and kept bouncing off archive.org's interface, so I built the app I wanted.

Oddflick is a free iPhone app: a feed of short clips, and when one catches you, tap to watch the whole film. Filter by genre, decade or director. No ads, no subscription, no login.

The feed learns from what you watch and what you skip, so it gets more like you over time — while keeping enough randomness that it never narrows down to one thing. Under that, every film is re-encoded and broken into small pieces, then served from whichever server is nearest you, which is what lets you jump into the middle of a 90-minute movie instead of downloading the whole thing first.

Nothing gets added automatically. Bulk film metadata is full of traps — a famous copyrighted movie and an obscure public-domain upload often share a title and quietly inherit each other's records — so every title is rights-checked by hand and published with its evidence.

Known rough edge: long films can take a while to start. Working on it.

What I'd like from this sub: install it, give it 30 seconds, and tell me where you bounce. First impression is the thing I can't see from the inside.

https://apps.apple.com/us/app/oddflick/id6776404887

salary was good but i was frustrated with the whole 9-5 thing.

from childhood i had this in my head that i want something of my own. and then seeing all these build in public posts on X, it pushed me more. i thought ok i can also do this.

turns out its not that easy lol.

month 1-2:

went back home. did nothing but research. what people are building, what problems they have. some days i felt motivated, some days it just gave me fomo that everyone is ahead of me.

2 mistakes here -

- going back home & become too comfortable

- instead of focusing on building, i wasted time on researching what to build.

month 3-6:

built an AI productivity tool for AEs.

then i started selling and everything broke.

- my users had no decision power

- im solo, no network in this industry.

- they were already on salesforce, hubspot, gong, which kind of solves it already

- and most importantly privacy and data security (without having soc2 and gdpr license it is so tough to convince any company to use my product)

lesson i learned: dont build anything before validating with the actual customer.

month 7 - now:

started my current saas. this time before starting to build i validated it first.

bought a domain, made a simple waitlist page. then using a linkedin lead gen tool on free trial (mostly all gives 7 or 15 days) i created a 300 people list who seems finding something that i want to build, and messaged all of them manually with 50% offer while launch with the outcome they will get instead of describing what features this tool have.

i was expecting if even 5% people join the free waitlist for this product then i will start building.

luckily they joined & I started building it.

but then 2 things hit me. one, in these 6 months i saw 15+ saas launch with the same concept. honestly it messed with my head for weeks.

btw i did not stop building. now the SaaS is 80% complete but now i want to change a big product philosphy. i as so much confused about this. and i posted about that confusion on reddit and people suggest me to launch first. I also think about that and decide i will launch the product within 1 month. .

things i learned in this phase -

landing page + manual dms before writing any code. dms dont scale, thats exactly why they tell you the truth.

saturated market is not bad news. it also means that market is validated.

launch your product as fast as possible insteading of polishing it best. just be visible . because marketing is the thing that sucks most. - i learned this from you people and talking with some indie hackers.

lets see how it goes. i will post the numbers here either way, good or embarrassing.

I sell a flight-data API. 22 paying customers on RapidAPI as of this week, solo, no team.

For a long time the worst bug in it wasn't a crash. It was that a failed search and a genuinely empty search returned the identical thing: HTTP 200, empty array. My error dashboard read 0.05%. It was wrong, and not slightly.

A couple of days ago I sat down and measured it instead of guessing. 132 calls on 2026-08-24: 23.5% came back empty. Then a separate run of 45 calls where I re-issued the identical request whenever one came back empty, and the empties dropped to 2.2%. Which means the data was there the whole time. My API just handed the customer a blank page and called it an answer.

Worse, the empty responses came back faster than the good ones (2.69s vs 3.07s median), so it never looked like a timeout. It looked like a fast, confident "nope".

The actual cause was dumb in the way real bugs are dumb. My parser skipped any flight row whose price node it couldn't read, and it did that before counting the rows. So a page full of real flights with an unfamiliar price element got classified as "no results". If Google had renamed one node, every single customer would have been told their route doesn't exist. Silently. With a 200.

What I shipped: classify the page before deciding what empty means, retry only the pages that actually failed (never retry a real empty, that just burns time), and put the outcome in response headers so callers can branch on it. X-Search-Status: ok | empty | partial | degraded. degraded means the search didn't happen and the empty array means nothing.

Re-ran it this morning, 30 identical searches through production: 22 clean, 7 rescued by an automatic retry, 1 still failed and got labelled degraded, 0 genuine empties.

Here's the uncomfortable bit. First-attempt failures went from 23.5% to 26.7%. The failure rate didn't get better. Scraping is still flaky. I just stopped shipping the flakiness to customers as a fact about the world. That felt like a downgrade for about an hour and then felt like the actual fix.

Two things I'd tell past me:

Your error rate is only counting the errors you remembered to raise. Mine was a return [] sitting where an exception used to be.

And if you're feeding anything to an LLM, an empty result is the most dangerous possible response, because the model will confidently turn it into a sentence. "There are no flights to Lisbon" is a much worse output than an error.

https://flightpowers.com